1. Field of the Disclosure
The present disclosure relates to seals which may be used in an image forming apparatus. The seals may prevent the leakage of image forming materials, e.g., as between components and a housing in the image forming device. The image forming apparatus may include an electrophotographic device, ink printer, copier, fax, all-in-one device or multi-functional device.
2. Description of the Related Art
An image forming device, such as an electrophotographic device, ink printer, copier, fax, all-in-one device or multi-functional device may use developing agents such as toner or ink, which are stored in a cartridge and may be disposed on media to form an image. The developing agent, such as toner, may be fixed to the media using an image fixing apparatus, which may apply heat and/or pressure to the toner. Leakage of the toner from the cartridge may occur as it may be difficult to seal gaps between a rotating roll, a cleaning or doctor blade and the housing of the cartridge. Seals may be provided to effectively close the gaps and prevent toner leakage. Positioning of the roll against the seal and tolerance stack-up of the various mating components may create uneven stress and a non-uniform temperature profile. At higher printing speeds, heat may be generated due to the compression of the seal against the rotating roll causing the toner to melt. Design of the seal may therefore be an important factor in cartridge life.
Shown in FIGS. 1, 1A and 1B is a prior art seal 10. Seal 10 comprises a head 12, a toe 14, a rotary seal portion 16, a blade seal portion 20, a flap seal portion 22. A sealing surface 24 has a plurality of angled grooves 25 within the rotary seal portion 16. Blade seal portion 20 effects a seal between a doctor blade, a developer roll and a nip therebetween. Flap seal portion 22 effects a seal between a developer roll, a flap seal that runs along the length of the developer roll and a nip therebetween. To seal the two nips, projecting ribs 28 are provided on biasing surface 26. A feature of the ribs 28 is that they provide a uniform compressive force along their length. This is an effective design in systems having print speeds of 30 to 50 ppm (pages per minute) and lower. The seal 10 is designed to have sufficient compressive force to seal the two nips which requires a higher force than for example the force needed to seal along the developer roll within the rotary seal section 16. As printing speeds increase to even higher rates, for example 70-100 ppm, such a design using uniform compressive force produces unwanted frictional forces and heat along the rotary seal portion 16 of the seal 10. This unwanted heat may cause banding of the developer roll, or melting or agglomeration of the toner within an imaging apparatus leading to print defects. It would be advantageous to have a seal having areas of higher compressive force where needed such as at the nip locations and areas of lower compressive force where it is not required to provide an effective seal.